Polnatorhinus (often incorrectly spelt pomarinus), about the size of a common gull, Larus canus, and presenting, irrespective of sex, two very distinct phases of plumage, one almost wholly sooty-brown, the other particoloured - dark above and white on the breast, the sides of the neck being of a glossy straw-colour, and the lower part of the neck and the sides of the body barred with brown; but a singular feature in the adults of this species is that the two median tail-feathers, which are elongated, have their shaft twisted towards the tip, so that in flight the lower surfaces of their webs are pressed together vertically, giving the bird the appearance of having a disk attached to its tail.
Southwards (Shoa, Kobbo, Amuru) a decided chocolate and almost sooty black is the rule.
The commonest species in South America and the Antilles is the sooty or dusky A.
The hair varies from a sooty black to dark and light brown and red.
The sooty-grey colour that, deepening into blackish-brown on the crown and quills, pervades the whole of its plumage - the lower tailcoverts, which are of a deep chestnut, excepted - renders it a conspicuous object; and though, for some reason or other, far from being a favourite, it is always willing when undisturbed to become intimate with men's abodes.